Can I use my phone as a step counter?

I'm curious to know, can I really use my phone as a step counter? I mean, I've heard that some phones have built-in sensors that can track your movements, but is it accurate enough to use as a fitness tool? I'm looking to get more active and track my progress, so I'm wondering if relying on my phone for step counting is a viable option. What are the pros and cons of using a phone as a step counter compared to dedicated fitness trackers?